Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
Views 68125 Comment 0
랜덤함수 사용시..
iOS
There are several built-in randomizers on the iPhone, and most people's first thought is to use rand() after seeding it by calling
srandom(time(NULL));
But... rand() is really not a very good PRNG. random() is a little better, but still less then ideal. Fortunately, these are not the only ones available on the iPhone. Personally, I like arc4random() because it's a decent pseudo-random algorithm and has twice the range or rand().
On the iPhone, RAND_MAX is 0x7fffffff (2147483647), while arc4random() will return a maximum value of 0x100000000 (4294967296), giving much more precision. You also don't need to seed arc4random(), as the first call to it automatically seeds it.
결론은 arc4random() 을 사용하자.
[출처] http://iphonedevelopment.blogspot.com/2008/10/random-thoughts-rand-vs-arc4random.html
-
[ios] 아이폰용 앱 오픈 소스들
-
[doc] Json Framework 설치와 사용
-
[ios] iOS 4.0 beta 에서 3.1.3으로 다운그레이드 하는 법
-
[iphone] 아이폰 어플 모음 ㅋㅋ
-
[ios] 미스터피자(Mr.pizza) 어플
-
[ios] UIAlertView 초간단 샘플 ㅎㅎ
-
[ios] Random Thoughts: Rand() vs. arc4random()
-
[ios] 배열(NSArray) 연산과 간단한 애니메이션(split images)
-
[ios] iOS 6.0 이상 회전 하기 (이전 버전과 비교 변경 부분)
-
[ios] 언어, 지역, 국가 설정 가져오기
-
[ios] NavigationController 에서 왼쪽(back) 버튼 후킹하기
-
[ios] Did UIScrollView End Scrolling?